The present invention relates to an internal power control circuit for a semiconductor device and a method of controlling the supply of internal power, and more particularly, to an internal power control circuit having an improved capability for use in analyzing defects such as leakage current failure in semiconductor devices.
As semiconductor devices such as dynamic random access memory become more highly integrated, it is important to test whether the semiconductor device operates properly after the fabrication process and to find the causes of improper operation. In order to produce a perfectly operational product, various types of analyses must be performed on a product sample in the initial stages of development, and the analyses are very time-consuming. For these analyses, it is necessary that tests of operational characteristics and the detection of circuit malfunctions be performed at various levels of power voltage supplied to the semiconductor circuitry.
FIG. 1 shows a conventional internal power control circuit for a semiconductor device and its related circuitry. Referring to FIG. 1, in a normal operation mode, an internal power voltage generated by an internal voltage generator 130 in a semiconductor device 110 is supplied to memory cell arrays 120A, 120B, 120C, and 120D via an internal power supply line 150. When the operational characteristics of the semiconductor device are analyzed, each memory cell array 120A, 120B, 120C, and 120D is tested while the power generated from the internal voltage generator 130 is supplied thereto. In addition, the semiconductor device is tested while an external power voltage is applied thereto via a pad 140, while the internal voltage generator 130 is disabled or isolated from the internal power supply line 150.
As shown in FIG. 1, the internal power supply line 150 is commonly connected to each memory cell array 120A, 120B, 120C, and 120D. Thus, when either the voltage level or current level in the semiconductor device is abnormal, that is, when a defect is found during the testing process, it is difficult to determine which component is causing the defect. Particularly, when defects such as power bridges and current leakage are found, which often occur in the initial stages of development of a semiconductor device, it is difficult to find the exact source of the problem. Thus, much time is required to develop and test the semiconductor device.